Field of the Invention
The present invention relates to a method of transferring information indicating a reflecting surface of a rotating polygonal mirror.
Description of the Related Art
In an electrophotographic type image forming apparatus, a latent image is formed by a laser beam scanning a photosensitive body. A scanning apparatus of the image forming apparatus comprises a rotating polygonal mirror that deflects the laser beam. Although the rotating polygonal mirror has a plurality of reflecting surfaces, a reflection characteristic of each reflecting surface differs subtly. Thus, electronic correction of a scanning position of each reflecting surface becomes necessary. According to Japanese Patent Laid-Open No. 2006-142716, a technique for identifying each reflecting surface and for electronically correcting a scanning position by using correction data prepared for each reflecting surface is proposed.
A control unit for specifying the reflecting surface of the rotating polygonal mirror and an image processing module for electronically correcting the scanning position of each reflecting surface are independently integrated in the image forming apparatus. In such a case, a dedicated signal line for transmitting information indicating the reflecting surface that the control unit specified to the image processing module becomes necessary, leading to a cost increase for the image forming apparatus.